In this application for a mentored career award, the applicant seeks to expand the scope of his research efforts at Duke University Medical Center by applying novel approaches to investigation of hepatitis C virus (HCV) biology. It is anticipated that the proposed phase of mentored research will firmly establish the applicant's scientific independence and allow him to successfully compete for R01 research grant support in the future. The overall research objective of this career application is to identify and characterize molecular determinants of HCV replication that ultimately contribute to liver pathogenesis. HCV is a signficant [sic] human pathogen that chronically infects liver hepatocytes, often resulting in life-threatening complications. Three specific aims comprise the research proposal. I) The RNA genome of HCV has evolved unique functional elements to achieve replication within infected cells. Of particular interest, an internal ribosome entry site (IRES) located within the viral 5'untranslated region (UTR) recruits cellular ribosomes to mediate synthesis of viral proteins required for replication. We have discovered that the HCV IRES is dynamically regulated under conditions of cellular stress. Experiments proposed in specific aim I are designed to mechanistically decipher the role of cell stress in HCV protein synthesis and replication. II) RNA-protein interactions between the HCV genome and specific cellular factors are believed to facilitate virus replication, with direct implications for pathogenesis. We have identified multiple proteins that interact with the 3'UTR of HCV. Probing the functionality of these interactions in the context of HCV-infected cells is the subject of the second specific aim. Ill) The re-programming of cellular mRNA translation is a common theme in RNA virus infection, but knowledge of this phenomenon with regard to HCV is lacking. In specific aim III, we propose to employ a global approach to define mRNAs that are translationally regulated in response to HCV infection. These experiments will identify novel host pathways that are manipulated by HCV to benefit viral replication and persistence. Together, the experiments proposed by the applicant are expected to uncover novel molecular aspects of HCV infection that may be targeted therapeutically. PUBLIC HEALTH RELEVANCE: The hepatitis C virus (HCV) is a prominent human pathogen that chronically replicates within the liver of infected persons, often resulting in severe complications and death. The overall goal of the research proposed in this career award application is to understand, at the molecular level, how HCV manipulates host cells in order to ensure its own propagation.